1. Field of the Invention
The present invention relates to a method and an apparatus for preventing the intermixing of coolant, lubricant and combustion gases in an internal combustion engine in general and in particular to a method and apparatus comprising a novel head gasket which may be used separately or in combination with a novel insert for retaining coolant and lubricants within passageways provided therefor within such engines.
2. Description of the Prior Art
Typical automobile and truck engines comprise block assembly and a head assembly which are bolted together with a head gasket disposed therebetween. The block assembly comprises cylinder and piston assemblies and a plurality of passageways for circulating coolant and lubricant therein. The head assembly comprises intake and exhaust valve assemblies and, likewise, a plurality of passageways for circulating coolant and lubricant therein. The head gasket comprises a plurality of holes of various sizes and shapes to accommodate the cylinders, mounting bolts and openings in the fluid passageways which are used for circulating coolant and lubricant between the block and head assemblies.
During normal operation, relatively high internal temperatures and pressures are developed in the engine combustion chambers, coolant passageways and lubricant passageways. At the interface between the block and head assemblies, the only means available for isolating the combustion gases, coolant and lubricant is the head gasket.
Due to heat expansion, engine aging, extensive use, poor maintenance and/or poor operating techniques, the material in a conventional head gasket may deteriorate under fluid and gas pressure, allowing cooling fluid, e.g. steam, from the coolant passageways, oil from the lubricant passageway and gases from the combustion chambers to migrate through cracks or holes in the gasket and become mixed with the lubricant. This causes the lubricant to lose its lubricating properties, produces sludge, poor combustion, polluted exhaust and further deterioration of engine components, if not total engine failure.
One would expect that the openings of the coolant passageways in the block and head assemblies of a particular engine which are intended to be in communication with each other would be of a corresponding size and shape and that the manufacturer's recommended head gasket therefore would have holes of a corresponding size and shape. However, this is not the case with respect to many engines. On the contrary, it has been found that in many engines a number of the openings in the coolant passageways in the block assembly are of a different size and shape from those of the openings in the coolant passageways in the head assembly with which they are intended to communicate. Indeed, it has been found that sometimes the openings in the corresponding coolant passageways are not only of a different size and shape, but are also not aligned or are only partially in registration. Further, it has been found that often a head gasket which is recommended by a manufacturer for an engine has holes which do not conform in size and shape to the holes in the passageways in the block and head assemblies with which it is intended to be used and in some cases do not have one or more holes where a hole would be expected, thus blocking the passageway.
Another problem associated with conventional head gaskets is the proximity of the holes therein to each other. With holes relatively close to each other, e.g. a coolant hole and a combustion chamber hole, the probability of coolant migrating into the combustion chamber is significantly increased.